JP5738246B2 - Dual polarization antenna - Google Patents

Description

  The present invention relates to a polarization sharing antenna apparatus used in a mobile communication base station, and more particularly to a polarization diversity antenna that can independently transmit and receive two orthogonal polarizations.

  In base station antennas for mobile communication systems, printed dipole antenna elements are often used because of mass productivity and ease of electrical adjustment. A polarization diversity antenna using this printed dipole antenna element has been proposed by, for example, Patent Document 1.

In the antenna of this Patent Document 1, four element conductors having the same shape are formed on a dielectric substrate for elements at 90 ° intervals in a form in which a gap is formed at the center, and the element conductors positioned on the x-axis are The pair constitutes a first dipole antenna element for horizontal polarization, and the pair of element conductors positioned on the y-axis across the gap constitutes a second dipole antenna element for vertical polarization. ing. The four element conductors have a planar shape that gradually expands at a predetermined opening angle in a region from a vertex portion located on the gap side to a middle portion.
According to the polarization diversity antenna according to Patent Document 1, V. S. W. R. It is possible to obtain a broadband characteristic that a specific band satisfying <1.5 is about 42%.

JP 2011-244244 A

Currently, in Japan, 800 MHz band, 900 MHz band, 1.5 GHz band, and 2 GHz band are allocated as frequency bands used in mobile phones. However, for the purpose of data communication dispersion, the 2.4 GHz band (Wi- Fi), 2.5G band (WiMAX) is also beginning to be used.
Here, considering the 1.5 GHz band to the 2.5 GHz band, a specific band of about 60% is required, and therefore further broadbandization is required. In addition, a certain horizontal beam width within the above band is required due to the quality of the sector in the mobile communication base station.

  In view of such a situation, an object of the present invention is to provide a polarization-sharing antenna capable of further widening the band and making the beam width and gain uniform within the use band.

The present invention is first formed in a form that gap is formed in the center portion, and the second dipole antenna elements, said first dipole of each element conductor which constitutes the antenna element outer end and the front Stories second an outer end of each element conductor which constitutes a dipole antenna element is provided with, integrally connected annular conductor. Each element conductor constituting the first and second dipole antenna elements is set such that the width of the outer end is smaller than the width of the middle part, and the first conductor is formed by the first dipole antenna element and the annular conductor. The first folded dipole antenna element applied to the second polarized wave is configured, and the second folded dipole antenna element applied to the second polarized wave is configured by the second dipole antenna element and the annular conductor. Yes.

The form of implementation, the first, each element constituting the second dipole antenna element conductor and the annular conductor is printed formed in each element unit dielectric substrate.

  Further, as an embodiment, a first feeding portion dielectric substrate on which a feeding conductor for feeding power to the first dipole antenna element is printed and a feeding conductor for feeding power to the second dipole antenna element are printed. And a formed second power feeding portion dielectric substrate. The first and second feeder dielectric substrates are combined so as to cross each other, and the combined first and second feeder dielectric substrates are perpendicular to the surface of the element dielectric substrate. Combined.

The power feeding conductors of the first and second power feeding portion dielectric substrates can be provided so as to constitute a balun.
The first polarization and the second polarization are, for example, vertical polarization and horizontal polarization. The first polarization and the second polarization may be + 45 ° polarization and −45 ° polarization.
The element conductors constituting the first dipole antenna element and the element conductors constituting the second dipole antenna element may have different shapes and / or dimensions.

  It is also possible to construct a polarization-sharing antenna having an array structure by arranging the wave-sharing antennas having the above-described configuration in multiple stages in the vertical direction, the horizontal direction, or both the vertical and horizontal directions. It is also possible to add a reflector.

According to the present invention, the first dipole antenna element and the annular conductor constitute the first folded dipole antenna element applied to the first polarization, and the second dipole antenna element and the annular conductor provide the second. since it constitutes a second folded dipole antenna element antenna element to be applied to polarization, V. S. W. R. (Standing wave ratio) can be widened, and further wideband characteristics can be realized by making the element shape substantially elliptical and acting like a bow-tie antenna.

It is a perspective view which shows the polarization sharing antenna which concerns on one Embodiment of this invention. It is a top view which shows the structural example of an element part. It is a top view which shows the structure of an electric power feeding part. V. About Vertical Polarization of the Dual Polarization Antenna According to the Present Invention S. W. R. It is a graph which shows a characteristic. V. About horizontal polarization of the dual-polarized antenna according to the present invention. S. W. R. It is a graph which shows a characteristic. It is a graph which shows the directivity in a horizontal surface about the vertical polarization of the polarization sharing antenna which concerns on this invention. It is a graph which shows the directivity in a horizontal surface about the horizontal polarization of the polarization sharing antenna which concerns on this invention. It is a graph which shows the gain characteristic of the polarization sharing antenna which concerns on this invention. It is a perspective view which shows the polarization shared antenna of the array structure which concerns on this invention. It is a top view which shows the other shape of an element conductor. It is a top view which shows another shape of an element conductor.

FIG. 1 shows a polarization sharing antenna according to an embodiment of the present invention. The polarization-sharing antenna AN includes an element unit 10, power feeding units 20 and 30, a support plate 40 and a reflection plate 50.
FIG. 2 is a plan view illustrating a configuration example of the element unit 10. The element portion 10 has a configuration in which four element conductors 12 and an annular conductor 13 having the same shape are formed on a circular dielectric substrate 11.
The element conductors 12 have a substantially elliptical plane, and are arranged so that their major axes are spaced by 90 °, and a gap 14 is formed between their inner ends. Yes. The inner end portion of each element conductor 12 is tapered so as to be tapered.

  The pair of element conductors 12 positioned on the y axis with the gap 14 interposed therebetween constitutes a first dipole antenna element applied to one polarized wave (for example, vertically polarized wave), and the gap 14 is sandwiched therebetween. The pair of element conductors 12 positioned on the x-axis constitutes a second dipole antenna element applied to the other polarized wave (for example, horizontal polarized wave).

The annular conductor 13 is formed along the outer peripheral edge of the dielectric substrate 11 and is coupled to the outer end of each element conductor 12.
The annular conductor 13 is provided as a folded conductor of a folded dipole antenna (folded dipole antenna), and is combined with the first dipole antenna element to constitute a three-wire first folded dipole antenna element. In addition, a three-wire second folded dipole antenna element is configured in combination with the second dipole antenna element.
Each element conductor 12 and the annular conductor 13 are made of a metal foil (for example, copper foil) stuck on the dielectric substrate 11, and are printed using a so-called printed wiring pattern forming method.

The element conductor 12 in this embodiment has a length L1 set to about 0.24λ (λ is a wavelength of the center frequency of the used frequency band), and an intermediate width W1 is set to about 0.18λ. The first and second dipole antenna elements have a total length L2 of about 0.5λ.
The annular conductor 13 is set to have a width of about 0.006λ. The connection width W2 of each element conductor 12 to the annular conductor 13 is set to about 0.05λ.

Next, the configuration of the power feeding units 20 and 30 will be described with reference to FIG.
In the power feeding unit 20, a pair of ground conductors 22 a and 22 b are formed on one surface of the dielectric substrate 21, and a feed line conductor 23 is formed on the other surface of the dielectric substrate 21. Of course, the ground conductors 22a and 22b and the feed line conductor 23 are also printed with a metal foil.
The power feeding unit 20 is provided with tongues 25 a and 25 b on both sides of the upper end of the dielectric substrate 21, and tongues 26 a and 26 b on both sides of the lower end of the dielectric substrate 21.

  The ground conductors 22 a and 22 b are extended from the upper end to the lower end of the dielectric substrate 21 so as to have a line-symmetrical relationship with respect to the vertical center axis of the dielectric substrate 21. The strip-shaped metal-free foil portion 24 formed between the ground conductors 22a and 22b has a notch groove 27 that extends upward from the lower end thereof. In the present embodiment, the length of the metal-free foil portion 24 is about 0.25λ.

  The feed line conductor 23 extends upward from the lower end of the dielectric substrate 21 at the back of one of the ground conductors (in this embodiment, the ground conductor 22b), and then bends sideways over the back of the metal-free foil portion 24. It is formed so as to cross and then be folded downward at the back of the other ground conductor 22a. In the feeder line conductor 23, the length from the portion located at the midpoint of the metal-free foil portion 22 to the tip is set to about 0.25λ. Moreover, the lower end part of this feeder line conductor 23 is located in the back surface of the tongue piece 26b.

The other power supply unit 30 includes components 31, 32a, 32b, 33, 34, 35a, and 35b corresponding to the components 21, 22a, 22b, 23, 24, 25a, 25b, 26a, 26b, and 27 of the power supply unit 20. , 36a, 36b, 37.
However, the notch groove 37 extends downward from the upper end of the metal-free foil portion 34 and is different from the notch groove 27 of the power feeding unit 20 in this respect. The length of the notch groove 37 is set to be the same as the distance from the upper end of the notch groove 27 to the upper end of the metal-free foil portion 24.

  The power feeding units 20 and 30 are combined as follows. That is, a portion positioned below the lower end of the notch groove 37 in the power feeding unit 30 is inserted into the notch groove 27 of the power feeding unit 20, and The part above the upper end is inserted. Thus, the power feeding units 20 and 30 are combined and integrated in a form in which they cross each other as shown in FIG.

  As shown in FIG. 2, rectangular holes 15 penetrating the dielectric substrate 11 are formed in the inner end portions of the element conductors 12 of the element portion 10. In these four holes 15, tongue pieces 25 a, 25 b, 35 a, 35 b projecting upward from the integrated power feeding parts 20, 30 are inserted as shown in FIG. The power feeding units 20 and 30 are coupled vertically.

  The ground conductors 22a, 22b, 32a, and 32b shown in FIG. 3 are attached to the tongues 25a, 25b, 35a, and 35b protruding to the upper surface side of the dielectric substrate 11, respectively. Therefore, one and the other element conductors 12 positioned on the x-axis in FIG. 2 are electrically connected to the ground conductors 22a and 22b of the tongue pieces 25a and 25b by means of solder or the like, respectively. One and the other element conductors 12 positioned on the shaft are electrically connected to the ground conductors 32a and 32b of the tongue pieces 35a and 35b using the same means.

The support plate 40 in FIG. 1 is made of a dielectric material. The integrated power feeding portions 20 and 30 are fixedly supported by the support plate 40 by inserting tongue pieces 26a, 26b, 36a and 36b projecting downward therefrom into holes formed in the support plate 40. ing.
The ground conductors 22a, 22b, 32a, 32b attached to the surfaces of the inserted tongue pieces 26a, 26b, 36a, 36b, and the feed line conductor 23 attached to the back surface of the inserted tongue pieces 26b, 36b. 33 are electrically connected to a feeder line conductor (not shown) printed on the support plate 40 by means of solder or the like.
The reflection plate 50 is provided on the back portion of the support plate 40. In the present embodiment, the reflection plate 50 is provided at a position separated from the element conductor 12 of the element unit 10 by about 0.26λ.

  In the dual-polarized antenna AN according to the present embodiment configured as described above, the ground conductors 22a and 22b (ground parts) on the tongue pieces 26a and 26b shown in FIG. Connected to the outer conductor of the first coaxial cable (not shown), and the base end of the feeder line conductor 23 is connected to the inner conductor of the first coaxial cable via the feeder line conductor of the support plate 40. Is done.

  Similarly, the outer conductors of the second coaxial cable (not shown) are connected to the ground conductors 32a and 32b (grounding portions) on the tongue pieces 36a and 36b shown in FIG. 3 via the feeder line conductor of the support plate 40 shown in FIG. In addition, the base end portion of the feed line conductor 33 is connected to the inner conductor of the second coaxial cable via the feed line conductor of the support plate 40.

  Next, the operation of the polarization sharing antenna AN according to this embodiment will be described. However, here, the first folded dipole antenna element including the pair of element conductors 12 positioned on the y-axis in FIG. 2 is applied to vertical polarization, and the pair of element conductors 12 positioned on the x-axis is The second folded dipole antenna element that is included shall be applied to horizontal polarization.

The first folded dipole antenna element for vertical polarization is fed through the feeding unit 20, and the second folded dipole antenna element for horizontal polarization is fed through the feeding unit 30.
That is, the first folded dipole antenna element is excited by being fed from the bent transverse portion of the feed line conductor 23 shown in FIG. 3, and the second folded dipole antenna element is fed by the feed line conductor 33 shown in FIG. The power is fed from the bending cross section of the motor and excited.
At this time, the ground conductors 22a and 22b and the feed line conductor 23 function as a balun (balance-unbalance converter), and the ground conductors 32a and 32b and the feed line conductor 33 also function as a balun.

By the way, since the first and second folded dipole antenna elements share the annular conductor 13 shown in FIG. 2 provided as the folded conductor, the influence between the annular conductors 13 is reduced as much as possible. It is desirable.
In the polarization sharing antenna AN according to the present embodiment, the width of the outer end portion of the element conductor 12 is set smaller than the width of the intermediate portion, so that the connection area of the element conductor 12 to the annular conductor 13 is reduced. By reducing the influence between the first and second folded dipole antenna elements, it is possible to obtain broadband characteristics as will be described later.

4 and 5 show V.V. for vertical polarization and horizontal polarization of the polarization sharing antenna AN according to this embodiment. S. W. R. Each characteristic is shown. As is clear from these figures, according to the polarization sharing antenna AN according to this embodiment, V. S. W. R. It is possible to make the ratio band satisfying 1.5 or less about 60%, that is, to improve the broadband characteristics. F ₀ is the center frequency.

On the other hand, FIG.6 and FIG.7 shows the horizontal-plane directivity characteristic about the vertical polarization and horizontal polarization of the polarization sharing antenna AN which concern on this embodiment, respectively. As is clear from these figures, according to the dual-polarized antenna AN according to this embodiment, it is possible to obtain a substantially constant beam width within the specific band.
Further, according to the dual-polarized antenna AN according to the present embodiment, as shown in FIG. 8, it is possible to obtain a substantially constant gain characteristic in the specific band for both the vertical polarization and the horizontal polarization.

  FIG. 9 shows an embodiment of a polarization diversity antenna having an array configuration in which a plurality (two in this example) of the polarization-sharing antennas AN are arranged at predetermined intervals in the vertical direction. In the polarization diversity antenna having this array configuration, a support plate 40 ′ and a reflection plate 50 ′ that are commonly used in each antenna AN are provided. According to the dual-polarized antenna having this array configuration, gain can be improved.

The present invention is not limited to the above embodiment, and can include various modifications as exemplified below.
(A) The shape of the element conductor formed in the element part 10 is not limited to the shape shown in FIG. That is, if the condition that the inner end portion and the outer end portion are smaller in width than the intermediate portion is satisfied, for example, element conductors 12 ′ and 12 ″ shown in FIGS. 10 and 11 can be used. The element conductor 12 'shown in Fig. 10 is formed in a polygonal shape, and the element conductor element 12 "shown in Fig. 11 has a shape in which a rectangular sub-part 12B is added to the inner side of a substantially elliptical main part 12a. Have.
(B) When a reflecting plate is arranged or an array structure is used, the influence of these on the operation of the antenna may be different for one polarization and the other. In the antenna according to the present invention, the above difference can be corrected by making the shape (dimension) of one polarization element conductor different from the shape (dimension) of the other polarization element conductor. It is.
(C) It is also possible to change the arrangement form of the element conductors 12 so that they can be shared by ± 45 degree polarization.
(D) In the embodiment of FIG. 9, the number of stages is set in the vertical direction. However, the number of stages can be set in the horizontal direction. Further, it may be multistaged in both the vertical direction and the horizontal direction as necessary.

DESCRIPTION OF SYMBOLS 10 Element part 11 Dielectric board | substrate 12,12 ', 12 "Element conductor 13 Annular conductor 14 Gap 15 Hole 20,30 Feed part 21,31 Dielectric board 22a, 22b Grounding conductor 23,33 Feed line conductor 24,34 Non-metal Foil portion 25a, 25b, 35a, 35b tongue 26a, 26b, 36a, 36b tongue 40, 40 'support plate 50, 50' reflector

Claims (9)

First and second dipole antenna elements formed in a form in which a gap is formed in the center;
And a piece connected to an annular conductor and the outer end of each element conductor constituting the front Stories second dipole antenna element and the outer end of the element conductor which constitutes said first dipole antenna element,
Each element conductor constituting the first and second dipole antenna elements is set such that the width of the outer end portion is smaller than the width of the intermediate portion,
The first dipole antenna element and the annular conductor constitute a first folded dipole antenna element to be applied to the first polarization, and the second dipole antenna element and the annular conductor constitute a second polarization. A dual-polarized antenna comprising a second folded dipole antenna element applied to a wave.   2. The polarization sharing antenna according to claim 1, wherein each of the element conductors and the annular conductors constituting the first and second dipole antenna elements is printed on an element part dielectric substrate. A first feeding portion dielectric substrate on which a feeding conductor for feeding power to the first dipole antenna element is printed;
A second feeding portion dielectric substrate on which a feeding conductor for feeding power to the second dipole antenna element is printed;
The first and second feeder dielectric substrates are combined so as to cross each other, and the combined first and second feeder dielectric substrates are coupled vertically to the surface of the element dielectric substrate. The dual-polarized antenna according to claim 2.   4. The dual-polarized antenna according to claim 3, wherein the feeding conductors of the first and second feeding unit dielectric substrates are provided to form a balun. 5.   5. The dual-polarized antenna according to claim 1, wherein the first polarization and the second polarization are a vertical polarization and a horizontal polarization, respectively.   5. The dual-polarized antenna according to claim 1, wherein the first polarization and the second polarization are + 45 ° polarization and −45 ° polarization, respectively.   The shape and / or size of each element conductor constituting the first dipole antenna element and each element conductor constituting the second dipole antenna element are different from each other. The dual-polarized antenna described.   8. A dual-polarized antenna having an array structure, wherein the dual-polarized antenna according to claim 1 is arranged in multiple stages in the vertical direction, the horizontal direction, or both the vertical direction and the horizontal direction.   9. The dual-polarized antenna according to claim 1, further comprising a reflector.

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